/* 
 * Copyright (c) 2004, Cameron Zemek
 * 
 * This file is part of JExpression.
 * 
 * JExpression is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * JExpression is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package net.sf.jeppers.expression.function;

import java.math.BigDecimal;
import java.util.*;

/**
 * @author <a href="mailto:grom@capsicumcorp.com">Cameron Zemek</a>
 */
public class Average extends AbstractFunction {
	public Object run(List arguments) throws InvalidArguments {
		checkArgumentList(arguments);
		
		BigDecimal total = new BigDecimal(0);
		int noArgs = arguments.size();
		
		// If no arguments then return an average of 0
		if (noArgs == 0) {
			return total;
		}
		
		for (Iterator it = arguments.iterator(); it.hasNext(); ) {
			total = total.add(new BigDecimal(it.next().toString()));
		}

		return total.divide(new BigDecimal(noArgs), 31, BigDecimal.ROUND_HALF_EVEN);
	}

	public int getNumberOfArguments() {
		return -1;
	}
}
